Local Email Collection
Where this stands
One published detection covers this technique. Every one is unverified — no rule on Siemphony has been executed against real telemetry.
What the technique is
Adversaries may target user email on local systems to collect sensitive information. Files containing email data can be acquired from a user’s local system, such as Outlook storage or cache files. Outlook stores data locally in offline data files with an extension of.ost. Outlook 2010 and later supports.ost file sizes up to 50GB, while earlier versions of Outlook support up to 20GB. IMAP accounts in Outlook 2013 (and earlier) and POP accounts use Outlook Data Files (.pst) as opposed to.ost, whereas IMAP accounts in Outlook 2016 (and later) use.ost files. Both types of Outlook data files are typically stored in C:\Users\\Documents\Outlook Files or C:\Users\\AppData\Local\Microsoft\Outlook.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN0130
Detection focuses on processes that attempt to locate, access, or exfiltrate local Outlook data files (.pst/.ost) using file system access, native Windows utilities (e.g., PowerShell, WMI), or remote access tools with file browsing capabilities. The behavior chain includes directory enumeration, file access, optional compression or staging, and network transfer.
Technique names and descriptions © MITRE ATT&CK®, CC BY 4.0. Not endorsed by MITRE.